Select Committee on Science and Technology Fifth Report


Seating and space

6.33 We consider those points in more detail elsewhere in this Report, but turn immediately to one of the most closely related issues - seating and space - about which we have received many representations. As noted in paragraph 3.50, the JAA and CAA regulatory requirements for seating relate only to safety. They do not include any consideration of passenger comfort, and there is no regulation to relate either passenger numbers or seat spacing to the type of operation concerned.

6.34 Modern passenger airliners are of two basic types:

    (a)  short-haul narrow-bodied aircraft which generally carry between 50 and 200 passengers up to about 3,000 miles (or some 6 hours flying time) and have one central aisle with seats distributed in single, double or triple bank rows on either side; and

    (b)  long-haul wide-bodied aircraft which typically carry between 250 and 450 passengers over longer distances of up to about 8,000 miles[86] (or some 14 hours flying time) and have two cabin aisles with double or triple bank seat rows on the outer sides and rows of four, five or six seats between the aisles.

6.35 The basic trends of civil airliner development have been and seem to be continuing to be towards larger aircraft carrying more passengers for longer distances[87]. As a result, new routes may be opened up over remote territories and oceans. Non-stop flight sectors in excess of 18 hours are envisaged (Q 354). Such developments may not be welcomed universally because of the implications for passenger health. The International Airline Passenger Association (IAPA), for instance, was particularly concerned about these trends (p 243). There must be concern over whether any potentially adverse health implications of the aircraft cabin environment will be exacerbated by the increasing size of aircraft, the increased passenger numbers being carried in such aircraft, and the increasing duration of non-stop flights. There are also questions about the management of on-board safety and medical emergencies when a future very large aircraft may be many hours flying time from a suitable diversion airport. We are aware that aircraft manufacturers, aviation regulators, and airlines are studying these scenarios (p 130, Q 379), and we welcome this.

6.36 The descriptions in paragraph 6.34 refer to aircraft configured throughout for the basic economy or traveller class, but aircraft (particularly those intended for scheduled services) generally provide for several classes, greatly differentiated by ticket price. In our consideration of seating, space and mobility, we have concentrated on economy class passengers. They not only form the vast majority of airline passengers but also have the least generous provision and are thus most exposed to any potentially adverse health effects.

6.37 The profitability of an airline, like any other form of passenger transport, depends on providing and selling enough seats to enough customers at sufficient prices to ensure an adequate return on capital investment and operating costs. Thus there must be a successful balance between installing enough seats in a fixed space at an acceptable comfort level and selling them at a price to attract sufficient customers in a very highly competitive market (QQ 279-295, p 243). Subject to the minimum safety requirements for seating, space and mobility noted in paragraphs 3.49ff, the trade-off clearly seems to be between seat space and price.


6.38 It is not straightforward to establish just what seat sizes are. The term "seat pitch" is an airline term for the distance between identical fixed points on the seat and the seat ahead, from which the calculation of how many rows of seats fit into a certain distance is straightforward. That measure makes no allowance for the thickness of the seat back, and a more useful measure for passengers' information is the distance from the seat behind the base of the spine to the back of the seat in front: indeed, it is this measurement which the UK safety regulators use[88] (QQ 289 & 290), and which Airworthiness Notice 64 requires to be a minimum of 26 inches (paragraph 3.49). People would normally refer to this measurement as "leg-room" but airlines seem to use this phrase differently (QQ 281-285).

6.39 The term "seat width" is also ambiguous. As far as elbow room is concerned, this is the lateral space available between the centre-lines of the left and right armrests. For the hips, however, the measure should be the distance between the inner surfaces of the left and right armrests - perhaps, as Miss Stringer suggested (Appendix 4) with some allowance for the audio-visual controls that are often placed on the inside surface of one of the armrests. The need for better definitions is discussed further in paragraph 6.49 below.

6.40 There are some complicated marketing considerations for operators, reflected in a range of available seat room. The Consumers' Association submitted a copy of a recent survey[89] (p 59) which found that seat pitch[90] in short-haul economy class ranged from 28 to 32 inches, and seat width from 15.5 to 20 inches. In long-haul economy class, seat pitch ranged from 28 to 34 inches and seat width from 16.2 to 18 inches. If the seat back is two inches thick, a seat pitch of 28 inches is the bare minimum that the UK safety regulations permit.


6.41 Seat design, space and configuration are clearly important in marketing and competition terms. Although we are concentrating in this section on economy class passengers, the marketing interplay with business and first class options cannot be ignored.

6.42 Until recently, it appears that little or no marketing consideration was given to any potential relationship between seat size (and associated mobility restrictions) and passenger health. We were told by BATA (Q 279), JAA (p 130) and others that there was no evidence that seat space, in itself, had any adverse impact on the health of airline passengers. However, as concerns have grown that restrictive seating might be detrimental to health, particularly in relation to the risk of DVT, airline marketers have begun to include health considerations as well as simple comfort factors in their trade-off calculations (Q 277).

6.43 Representatives of the airlines assured us that there was effective medical and passenger input into these deliberations (QQ 276-278), and Dr Bagshaw said that British Airways were fitting new economy seats giving better leg room in response to passenger concerns (Q 286). This does not necessarily suggest that airlines acknowledge a contribution from restrictive seating to health risks, but it is to be hoped that it demonstrates that medical input carries some weight in deliberations on the trade-offs between seat size and price.

6.44 As demonstrated by a number of the submissions summarised in Appendix 4, there is strong public demand for increased seat space in economy class, generally accepting the prospect of a modest increase in prices. In large measure, this reflects comfort considerations as more people are flying longer distances. It also reflects some concern over health, although perhaps among only a small proportion of airline passengers.

6.45 Some seats with extra leg-room (front of cabin, escape rows etc.) are already available on most flights but this is of limited use to those passengers who might need or want them unless they can be pre-booked. The Holiday Which? survey mentioned in paragraph 6.40 found that extra leg-room was pre-bookable on only about half the flights studied. The airlines said the situation was still patchy, but they were continuing to respond to this emerging market demand (QQ 293-296, p 104).

6.46 It is not unreasonable for passengers to want to know, at the time of booking, what size of seat is on offer for them to purchase. Airlines with varied fleets may have difficulty in answering such questions because of possible uncertainty until shortly before the flight about which aircraft will actually be used. Even so, airlines should know of the possible permutations. We urge airlines not only to be more open about what it is that their customers are being sold but also to develop the options for pre-booking seats with extra leg-room.

6.47 BATA said the demand for seats with extra space as a result of normal cabin layout was only modest (Q 279), but we feel that this may reflect the current uncertainty about what is actually on offer. BATA further estimated that adding a couple of inches to existing seat pitch would put fare prices up by about 10% (p 124). British Airways estimated that 15-20% of economy class passengers might pay a small premium for increased seat pitch (Q 296). These considerations have led them, Virgin Atlantic and a number of other airlines to introduce a super-economy class with more spacious seating (QQ 279, 292 & 296, p 107).


6.48 We believe that the introduction of "premium economy" seating is a good answer to the demand for space above a reasonable minimum. We recognise - and the industry needs fully to recognise - that there is no such thing as a standard passenger with standard aspirations. Indeed, we were struck by the fact that some of the more sensational journalism about DVT and seating (on which we comment in paragraphs 8.35ff) appeared in the travel section of newspapers alongside pages of advertisements for the cheapest flights in what must be, almost by definition, minimum standard seating. Passengers are, of course, free to purchase whatever seating they wish. The point we make several times in this Report is that passengers' choices should be properly informed.

6.49 To facilitate passengers' choice of seating, we recommend CAA to use its current research (as welcomed in paragraph 3.51) to develop an unambiguous set of definitions for seat dimensions. The key issues are: the minimum size of seat taking account of health considerations; accommodation of passengers above average size; and proper allowance for seat-space reductions from the seat in front being reclined, material in seat-back pockets and fold-down tables.

6.50 That research may also point the way to new minimum standards. We understand BATA's concern that UK airlines should not be disadvantaged in a diverse and global market by a higher minimum standard than its international competitors. That simply strengthens the arguments in paragraph 6.31 for the industry as a whole and the international regulators to review seating arrangements.


6.51 Our concern is not only about seat sizes but also for space to move around the cabin. We received a number of representations (Appendix 4 and others) that limited space for out-of-seat movement may also have a substantial adverse impact on health. The airlines recognise the need for movement in their various in-flight media (QQ 297 & 298). BATA drew our attention to Britannia's practice on long-haul flights of making an announcement about moving round the cabin when appropriate, not least to get drinks from central water fountains (p 124). However, Dr Bown (Appendix 4) and Ms Vivienne Williams (p 292) are not alone in feeling that, far from encouraging passenger exercise and mobility, the reality is that some airlines actively discourage this. As noted in paragraph 6.31(f), we look to the regulators and the industry as a whole to address this.

Comfort, stress and health

6.52 We have already considered two of the main comfort aspects of the aircraft cabin: the thermal environment (paragraphs 5.37ff) and seating (paragraphs 6.33ff). Before turning to the interaction between comfort and health, we also briefly consider in-flight cabin noise.


6.53 There are no specific regulatory requirements concerning cabin noise levels. Airbus Industrie (p 165), British Airways (p 99) and Emirates (p 229) indicated that cabin ambient noise was well below those levels where passenger or crew health would be a source of concern.

6.54 Cabin noise arises from many sources: air passing rapidly (at speeds approaching 600 miles per hour) over the aircraft; the engines, transmitted through the aircraft structure and, particularly behind the wings, through the surrounding air; ventilating air passing through the inlet and outlet vents; in-flight entertainment; conversation (perhaps louder than in normal surroundings given the other noise); and other cabin activities.

6.55 It is difficult to see how the principal causes of in-flight cabin noise, engine and air noise, could be substantially reduced at reasonable cost. Appreciation of this may explain why, other than from the Royal College of Surgeons of Edinburgh (p 283) and Mr Sparks (Appendix 4), we received few representations that the levels should be lower. However, earplugs are useful in reducing annoyance from noise, particularly on overnight flights where passengers are seeking to sleep. We understand that these are routinely offered to first and business class passengers, and we recommend airlines to extend the inexpensive courtesy of offering free earplugs to all passengers.

6.56 That does not mean that in-flight noise is not an issue - and it may be particularly so in small aircraft. CAA mentioned noise and low frequency vibration as something which may have adverse health effects (p 16) and HSE identified noise as a particular matter meriting further research (p 23).

6.57 BALPA made the point on behalf of pilots that, although cockpit background noise is within acceptable limits, the addition of radio communication noise can cause the noise at the ear to exceed levels at which hearing protection would be required by law if flight-decks were not exempt from the Noise at Work Regulations (p 213). As this may have both health and wider safety implications, we recommend CAA and HSE to investigate the matter further.


6.58 We asked for views and evidence about interactions between comfort, stress and health, and discussed these with a number of our witnesses. It was generally agreed that there was a complex relationship between them, and that the air-travel experience as a whole had widely different effects on individuals. As concisely summarised by Mr Smethers of DETR (QQ 65-69) and the Public Health Minister (QQ 539 & 540), informed personal choice seems, as in many other areas, to be the key.

6.59 Professors Moyle and Muir of Cranfield University College of Aeronautics provided us with valuable material on environmental and stress factors associated with air travel - and their singular and additive impact on health and wellbeing - both in their evidence (p 218), and in earlier research proposals that they had generated. The Electro-Magnetism and Biocompatibility Association also provided us with a very wide-ranging overview of the factors to be considered when assessing the potentially adverse impact of the aircraft cabin environment on crew and passenger health (p 226).

6.60 Our discussion of seating and space was largely in connection with our principal concern with DVT, particularly for already at-risk groups. We have some sympathy with the additional concerns that discomfort and frustration from restrictive seating and difficulties of moving about add to the general stress of flying. It is widely perceived that discomfort and stress have a negative impact on health and wellbeing. It is important to note that stress is not just a mental state: it has physiological consequences such as increased rates of heartbeat and breathing.

6.61 IAPA, AsMA, Dr Dawood and others expressed concern that aircraft manufacturers, cabin designers, airline operators and airport authorities pay little or no attention to these matters (pp 243, 198 & 220, Annex 4). However, as Mr Smethers of DETR indicated (Q 68), stress is a personal matter, and airlines and their customers each have to make commercial choices in trying to achieve a balance between what is desirable and the cost involved.

6.62 The most commonly quoted of many factors associated with stress and air travel are listed in Box 5, and we emphasise that these include pre-flight activities. It is important to note that few of these factors are likely to be experienced in isolation, and effects on individuals may be compounded by multiple interactions. In our view, some of these factors, particularly in combination, may well give rise to the feelings of general malaise which people often attribute to poor quality cabin air. Even if such factors do not give rise to illness itself, they may cause detriment to the condition of the ailing or infirm.[91]

Box 5

Factors associated with stress and air travel


•  General preparations for travel.

•  Journey, which may include feeder flight, to the airport.

•  Airport tumult: transport; managing luggage; queues for check-in; crowded waiting, refreshment and toilet facilities; getting to the gate or bussing to the aircraft, ground delays at gate and on apron; fumes.

•  Aircraft constraints: family separation; seating discomfort; mobility limitations; inadequate baggage stowage; perceived inadequate toilet facilities.

•  Cabin environment: low humidity; inability to control thermal conditions; vibration and noise.

•  Cabin environment: low pressure and low oxygen as potential augmentors for other factors.

•  Turbulence in flight.

•  Duration of flight without stops.

•  Flight and airport changes during journey.

•  Time-zone changes, fatigue, and inability to sleep.

•  Excessive alcohol consumption.


•  Fear of flying.

•  Anxiety about unfamiliar airport or procedures.

•  Flight cancellations and delays.

•  Regimentation, boredom, and loss of personal control.

•  Claustrophobia.

•  For smokers, enforced non-smoking.

•  Concerns about destination, immigration control, baggage, and connecting flights or other onward travel.

Principal Sources: Aerospace Medical Association (p 198), BAE Systems (p 200), Cranfield University (p 218), Royal College of Nursing (p 277), individual cases in Appendix 4

6.63 We have become increasingly aware of the unique nature of the aircraft cabin environment, and of air travel itself, in terms of their potential impact on the health and wellbeing of passengers and crew. Noting the inter-relationship between comfort and stress and health, together with the scope for combined adverse effect with other environmental factors, we recommend that, when investigations are conducted into the impact of any particular environmental factor on health or wellbeing, the possibility of combined effects be given appropriate attention. Putting this the other way round, we agree with AsMA (p 198) that it is very unlikely that any ailment alleged to be due to the cabin environment would be found to be caused by a single factor, and that measures intended to alleviate a given health concern must take into account the interaction of a number of environmental factors.


6.64 A particular example of where combined effects appear to be at work is jet-lag. We received extensive evidence on this from Inflight Research Services (IRS - p 240) and the Research Institute for Sport and Exercise Sciences (RISES - p 269). It seems clear that the malaise of jet-lag is more than the result of crossing time zones about which, of course, nothing can be done. IRS notes particularly that the severity of jet-lag is connected with the relative discomfort of the flight. RISES made the point, reinforced by Professor Denison (p 94) and Boeing (p 204), that jet-lag was not a minor matter. It may have serious effects on judgement and impair performance. Boeing also pointed out that it may not be possible for frequent international travellers or long-haul flight crew to become acclimatised to jet-lag (p 204).

6.65 RISES indicated that enough was known about jet-lag for simple helpful information to be given to travellers and also thought that the general arrangements regarding in-flight entertainment and meals should take more note of scientific knowledge in this area. We agree with RISES and recommend airlines to review their arrangements for the timing of refreshments and sleep periods on long-haul flights with jet-lag in mind, and also to advise passengers both at booking and in-flight about appropriate measures to deal with the effects.

86   Those travelling the longer distances are known as ultra-long-haul. Back

87   We incline to the view of IAPA that technical and environmental considerations are likely to stand in the way of developments in supersonic and sub-orbital travel (p 243). Back

88   We understand that the UK is unique in actually specifying a minimum measurement in this context.  Back

89   Are you sitting comfortably?, Holiday Which?, Spring 2000. Back

90   Although not always using this term in the strict sense defined in paragraph 6.38. Back

91   We have received no direct evidence on psychiatric matters. However, it is not difficult to envisage flight stress factors triggering or augmenting abnormal psychiatric states. Back

previous page contents next page

House of Lords home page Parliament home page House of Commons home page search page enquiries index

© Parliamentary copyright 2000